The present invention relates to a code string editing apparatus, a picture coded signal decoding apparatus and a moving picture coded signal decoding apparatus. More particularly, the present invention relates to a code string editing apparatus, a picture coded signal decoding apparatus and a moving picture coded signal decoding apparatus which are suitable for decoding a plurality of picture/moving picture coded signals into a single picture/moving picture.
A conventional picture coded signal decoding apparatus 1000 will be explained below by referring to FIG. 12. This picture coded signal decoding apparatus 1000 receives four picture coded signals and decodes these signals into one picture signal.
An example of the utilization of the picture coded signal decoding apparatus 1000 will be described below. Referring to FIG. 12, four picture signals Pa, Pb, Pc and Pd are generated for pictures taken by four cameras 1a, 1b, 1c and 1d respectively. The generated four picture signals Pa, Pb, Pc and Pd are coded into picture coded signals Ca, Cb, Cc and Cd by picture coding apparatuses 2a, 2b, 2c and 2d respectively. The coded picture coded signals Ca, Cb, Cc and Cd are transferred to the picture coded signal decoding apparatus 1000 through transmission paths 3a, 3b, 3c and 3d respectively. In the picture coded signal decoding apparatus 1000, the picture coded signals Ca, Cb, Cc and Cd are decoded into a picture signal P, which is then transmitted to a monitor unit 5 through a transmission path 4 and is displayed there as a composite picture.
The operation of the conventional picture coded signal decoding apparatus 1000 will be explained next. The picture coded signal decoding apparatus 1000 is structured to include four picture decoding units 1100a, 1100b, 1100c and 1100d and one picture composing unit 1200. In the picture coded signal decoding apparatus 1000, the four picture coded signals Ca, Cb, Cc and Cd are input through the four transmission paths 3a, 3b, 3c and 3d respectively. The input picture coded signals Ca, Cb, Cc and Cd are decoded into the picture signals Pa, Pb, Pc and Pd by the picture decoding units 1100a, 1100b, 1100c and 1100d respectively. The four picture signals Pa, Pb, Pc and Pd are sent to the picture composing unit 1200 and are then composed into the one picture signal P. The composite picture signal P is sent out to the transmission path 4.
According to the conventional picture coded signal decoding apparatus described above picture decoding units corresponding to the number of picture coded signals being input are necessary. In this example illustrated in FIG. 12, four picture coded signals are applied. Thus, four picture decoding units are necessary. If more than four picture coded signals are applied then more picture decoding units are necessary. Further, for each picture decoding unit used, peripheral circuits for operating the picture decoding units are necessary. As a result, it is difficult to make a compact and economical structure for a picture coded signal decoding apparatus.
Further, in order to correspond to a change in the number of input picture coded signals, it is necessary to change the number of picture decoding units in addition to the necessary change in the structure of the picture composing unit. Accordingly, it is difficult to change the number of picture coded signals that are input.
Also, in many cases, when a picture signal is coded, the picture signal is converted into a code of a smaller capacity highly efficiently. Thus, when a picture coded signal is decoded, the capacity of the code becomes larger. Accordingly, the picture composing unit needs to process picture information of a large capacity code resulting from the decoding of a small capacity picture coded signal. Therefore, a large processing capacity is required for the picture composing unit. A large processing capacity in the picture composing unit is particularly required when a fine picture including a large quantity of information is to be processed, or when a moving picture is to be processed based on a series of pictures received continuously.